Today I'm reviewing for you a fast midrange zoom for DX. It's Sigma, it's cheap, and it can offer you up to two stops of advantage (f/2.8 vs f/5.6 for a standard kit lens). Most (but by no means all!) of you suspect that there must be some compromise, and you wanna know where. Read on to find out.
+ constant f/2.8 aperture makes a difference when you need it.
+ image quality in mid- and tele-range excellent (stopped down a stop); wide-open very good.
+ very good value, you get what you pay and a bit more.
- wide-angle has some flaws (read 'Final Verdict' for details)
- chromatic aberrations quite visible.
- focal length range quite limited
|Wide-open at 18mm is as bad as it gets. So, if you see nothing wrong with this image, you'll like it|
- DX users who need one lens that is both good and cheap
- Concerts in dark clubs (provided you can get near the front)
- walk-around lens (as long as you don't need tele range)
- tele work, obviously. 50mm is too short.
- sports (see point above)
- if you're not shooting regularly in low light, you can find cheaper options (with longer reach, too)
Like with most midrange zooms, it's great value, if you need such a zoom. This Sigma is not a bad choice, but it has drawbacks you should know. The biggest issue is the weakness @18mm. The center is sharp alright, but the corners are far weaker - they get better two stops down.Chromatic aberrations are visible, and even software can't work wonders correcting some of them. Ultimately, if you mostly shoot in daylight or with flash, you could pass this one and opt for something like the Nikkor 18-105mm.